1. PITA to tack, especially with the clew and sheets of the staysail usually entangling on the fore(staysail)stay.
2. There is always a variable tension 'fight' between the headstay and the forestay depending on the sq. ft. area of each sail and windstrength.... and the 'usual is that the headstay will be too sack and thus reduced pointing ability. This is probably the chief reason that most cutter
rigs cant 'point' into the wind very well.
3.
rigging costs when replacing. The staysailstay (forestay) needs to be 'opposed' either by running backstays or 'intermediate' stays
4. VERY hard to get correct sail interaction between the headsail and the staysail.
Advantages ....
1. helm balance when deep reefed main and staysail only.
2. Beam reaching, etc. when the staysail 'fills in' the foretriangle for extra sail area.
3. on a 'true' cutter with the mast at about 50% of deck length a large genoa only (no other sails) will allow good up-wind performance ... the "CE" of the combined cutter sailing
rig is in front of the mast, a sloop has its CE 'behind' the mast.